(CNN) -- A source with knowledge of the investigation told CNN the state attorney's office believes there were two motives in the home invasion murder of Florida couple Byrd and Melanie Billings -- robbery and a contracted hit.

Leonard Patrick Gonzalez Jr., 35, is believed to be the organizer of Byrd and Melanie Billings' deaths.

The Escambia County Sheriff's Office had said it believed robbery was the prime motive, but that it would explore all avenues.

The source said the state attorney's office is working under the belief that most of the suspects in the case thought they were there for a robbery, but that Leonard Gonzalez Jr., the alleged organizer of the crime, and other yet-unnamed suspects were plotting a hit on the couple.

The source said that from "Gonzalez down" it was a robbery and that from "Gonzalez up" it was a hit. The source was not sure of the motive behind the hit.

The Escambia County Sheriff's Office has said it believed robbery was the prime motive, but that it would explore all avenues, a position Sheriff David Morgan reiterated Friday night.

"We are, in fact, looking at this," Morgan said. "We want to ensure the citizens of Escambia County that we are not in any way, shape or form of the imagination taking that possibility or probability off the table in the conduct of the Billings murder."

Morgan said that early in the investigation, investigators had "uncorroborated information that would lead a reasonable person to believe that this was an avenue of the investigation that we should in fact pursue." He added, "We have and will continue to do that very thing."

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"I want the citizens of Escambia County to understand that this investigation will go where it goes, and anyone who aided or abetted in the commission of this crime will be brought to justice," the sheriff said.

Greg Marcille of the Escambia County Office of the State Attorney did not deny that investigators were considering a contracted hit, but said his office believes "that the prime motive was robbery."

"We will consider all possibilities and review any evidence that is brought forward regarding the issue of motive in this case," he said.

The Billingses, who were known for adopting special-needs children, were killed during a robbery at their Beulah, Florida, home July 9.

A small safe containing prescription medication, family documents and some jewelry was taken, and later found in the backyard of a woman who said she was a friend of Gonzalez, authorities have said.

Two sources familiar with the investigation told CNN that a second safe at the home contained at least $100,000.

Eight people have been arrested in the case. Seven are facing murder charges and one is accused of being an accessory after the fact.

Escambia County Sheriff David Morgan has said Gonzalez once worked for a car dealership Byrd Billings owned, and court documents state that Gonzalez received financial support from the family for a martial-arts studio that he ran.

An attorney representing the Billingses has said that Byrd Billings made a nominal donation to Gonzalez's karate charity.